I'm seeing "Access to the port 'COM9' is denied" in the verbose.log when starting the TriPosService on Win10,
although I've gotten triPOS working successfully on Windows7 with the Verifone Mx915 for Authorizations.
The port shows as Mx Family POS Terminal (COM9) in Device Manager, "working correctly"
The triPOS API webpage shows correctly from http://localhost:8080/api/help
Version: triPOS 18.104.22.168406
From the verbose.log:
2018-04-09 15:37:45,687  triPOS TRACE - SerialClientTransport.cs.TryConnectClient: Is the COM9 serial port open?[False]
2018-04-09 15:37:45,703  triPOS ERROR - SerialClientTransport.cs.TryConnectClient: Error opening serial port
System.UnauthorizedAccessException: Access to the port 'COM9' is denied.
at System.IO.Ports.InternalResources.WinIOError(Int32 errorCode, String str)
at System.IO.Ports.SerialStream..ctor(String portName, Int32 baudRate, Parity parity, Int32 dataBits, StopBits stopBits, Int32 readTimeout, Int32 writeTimeout, Handshake handshake, Boolean dtrEnable, Boolean rtsEnable, Boolean discardNull, Byte parityReplace)
at .? .? ()
at . ? .ReopenConnection()
at . ? . ? ()
Enabling/Disabling ports in BIOS to match working Win7 machine made no difference.